-LRB- CNN -RRB- -- Former Colombian President Cesar Gaviria on Tuesday strongly criticized the United States ' approach to fighting drugs .

Cesar Gaviria highlighted the problems Mexico is facing handling its drug problem .

`` Just putting all consumers in jail , as the U.S. does , is not a solution , '' he told CNN 's Christiane Amanpour . `` You have to reduce consumption . ''

In a wide ranging interview , Gaviria said the United States now has more people in jail for narco-trafficking or related crimes than there are prisoners in the whole of Europe .

`` What you need to do with addicts and people who consume drugs is deal with them as a health problem , an education problem , '' he said .

Gaviria and two other former Latin American presidents -- Fernando Cardoso of Brazil and Ernesto Zedillo of Mexico -- are all arguing the war on drugs has failed and it is time to replace current policy with what they call a more humane and efficient approach .

Colombia remains the principal source of cocaine for the world , despite $ 6 billion in U.S. aid for anti-drug campaigns over the past decade . Watch the interview with Gaviria ''

Gaviria said it 's time the United States changed its approach . `` The U.S. has to look at its policy , to start to use more of that $ 4 billion a year that they use , to use more of the resources in the health system , in treatment and taking some people out of jail . ''

He highlighted the problems Mexico is facing handling its drug problem .

Thousands of people have been killed there in drug-related violence in recent years .

He said democracy in Mexico is paying a significant price , with major damage to its judicial system , its police , and its army .

`` The Mexicans probably in a few years will be able to deal a little better with the problems of security , '' he said . `` But the flow of drugs will keep growing . ''

He declared , `` We will never be successful unless the U.S. reduces consumption and Europeans do , also . ''

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Cesar Gavir argues that the war on drugs has failed

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Gavir : Time to replace current policy with `` more humane , efficient approach ''

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Colombia remains the principal source of cocaine for the world

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This is despite $ 6 billion in anti-drug aid from U.S. in past decade